Display Device Capable of Reducing the Number of Readout Wires for Receiving a Biometric Sensing Signal

1. A display device comprising: a display layer; and a sensor layer configured to sense an external input and disposed on the display layer, wherein the display layer includes: a plurality of pixels, each of which includes a light emitting element and a pixel driving circuit connected to the light emitting element; and a plurality of sensors, each of which includes a sensing element and a sensor driving circuit connected to the sensing element, wherein the sensor driving circuit includes: a reset transistor including a first electrode for receiving a reset voltage, a second electrode connected to a first sensing node, and a third electrode for receiving a first scan signal; an amplification transistor including a first electrode for receiving a first driving voltage, a second electrode connected to a second sensing node, and a third electrode connected to the first sensing node; an output transistor including a first electrode connected to the second sensing node, a second electrode connected to a sub-readout line, and a third electrode for receiving a second scan signal; and a switch transistor including a first electrode connected to the sub-readout line, a second electrode connected to a readout line, and a third electrode for receiving a switch signal generated based on the external input, wherein one readout line is shared as the readout line for at least two sensors among the plurality of sensors.

2. The display device of claim 1, wherein the sensor layer includes a plurality of first sensing electrodes and a plurality of second sensing electrodes crossing the plurality of first sensing electrodes, further comprising: a sensor controller configured to drive the sensor layer and including a signal generation circuit configured to transmit a transfer signal to the plurality of first sensing electrodes, an input detection circuit configured to receive a sensing signal from the plurality of second sensing electrodes, and a sensor control circuit.

3. The display device of claim 2, wherein the sensor controller generates the switch signal based on the sensing signal, and wherein the sensor controller outputs the switch signal to the switch transistor.

4. The display device of claim 2, wherein the sensor controller senses the external input based on the sensing signal, and wherein, in a plan view, the switch transistor included in each of sensors, which overlap the external input, from among the plurality of sensors is turned on in response to the switch signal.

5. The display device of claim 4, wherein, in the plan view, the switch transistor included in each of sensors, which do not overlap the external input, from among the plurality of sensors is turned off in response to the switch signal.

6. The display device of claim 4, further comprising: a driving controller configured to drive the display layer, wherein the driving controller controls pixels, which overlap the external input, of the plurality of pixels to emit light.

7. The display device of claim 2, wherein an active area, in which the plurality of pixels is disposed, and a peripheral area adjacent to the active area are defined in the display layer, further comprising: a sensing circuit disposed in the peripheral area, wherein the sensing circuit generates the switch signal based on the sensing signal, and wherein the sensing circuit outputs the switch signal to the switch transistor.

8. The display device of claim 1, wherein the display layer further includes: a fingerprint controller electrically connected to the plurality of sensors; and a multiplexer connected between the plurality of readout lines and the fingerprint controller.

9. The display device of claim 1, wherein the pixel driving circuit includes: a first transistor connected between the light emitting element and a first voltage line for receiving the first driving voltage; a second transistor connected between a data line and a first electrode of the first transistor and configured to receive the second scan signal; a third transistor connected between a second electrode of the first transistor and a first node and configured to receive the first scan signal; and a fourth transistor connected between the first node and an initialization voltage line and configured to receive a third scan signal, and wherein the third transistor and the fourth transistor have a transistor type different from a transistor type of the first transistor and the second transistor.

10. The display device of claim 9, wherein the reset transistor has a transistor type identical to the transistor type of the third transistor and the fourth transistor.

11. The display device of claim 10, wherein each of the third transistor, the fourth transistor, and the reset transistor is an NMOS transistor, and wherein each of the first transistor, the second transistor, the amplification transistor, and the output transistor is a PMOS transistor.

12. The display device of claim 10, wherein each of the third transistor, the fourth transistor, and the reset transistor is an oxide semiconductor transistor, and wherein each of the first transistor, the second transistor, the amplification transistor, and the output transistor is a low-temperature polycrystalline silicon (LTPS) transistor.

13. The display device of claim 1, wherein the light emitting element is an organic light emitting diode, and wherein the sensing element is an organic photodiode.

14. A driving method of a display device, the method comprising: providing the display device including a display layer including a plurality of pixels and a plurality of sensors, a sensor layer disposed on the display layer, a sensor controller configured to drive the sensor layer, and a fingerprint controller; sensing, by the sensor layer, an external input; sensing, by the sensor controller, a location of the external input; generating, by the sensor controller, a switch signal based on the location; outputting, by the sensor controller, the switch signal to the plurality of sensors such that only sensors that overlap the external input, from among the plurality of sensors, are turned on by the switch signal; electrically connecting a part of the plurality of sensors to the fingerprint controller based on the switch signal; and obtaining, by the part of the plurality of sensors, biometric information of the external input.

15. The method of claim 14, wherein each of the plurality of sensors includes a sensing element and a sensor driving circuit connected to the sensing element, and wherein the sensor driving circuit includes: a reset transistor including a first electrode for receiving a reset voltage, a second electrode connected to a first sensing node, and a third electrode for receiving a first scan signal; an amplification transistor including a first electrode for receiving a first driving voltage, a second electrode connected to a second sensing node, and a third electrode connected to the first sensing node; an output transistor including a first electrode connected to the second sensing node, a second electrode connected to a sub-readout line, and a third electrode for receiving a second scan signal; and a switch transistor including a first electrode connected to the sub-readout line, a second electrode connected to a readout line, and a third electrode for receiving the switch signal.

16. The method of claim 15, wherein the obtaining of the biometric information includes: a sensor initialization step in which the reset transistor is turned on; a sensor active step in which the sensing element receives light reflected from the external input; and a sensor sensing step in which the amplification transistor and the output transistor are turned on and a biometric sensing signal is provided to the readout line.

17. The method of claim 15, wherein the electrically connecting of the part of the plurality of sensors to the fingerprint controller includes: in a plan view, turning on the switch transistor included in each of sensors, which overlap the external input, from among the plurality of sensors in response to the switch signal.

18. The method of claim 14, wherein the sensor layer includes a plurality of first sensing electrodes and a plurality of second sensing electrodes crossing the plurality of first sensing electrodes, and wherein the sensing, by the sensor layer, of the external input includes: transmitting a transfer signal to the plurality of first sensing electrodes; and receiving a sensing signal from the plurality of second sensing electrodes.

19. The method of claim 18, wherein the sensing, by the sensor controller, of the location of the external input includes: calculating the location based on the sensing signal.